Long noncoding RNA NEAT1 promotes the growth of gastric cancer cells by regulating miR-497-5p/PIK3R1 axis

To investigate the molecular mechanisms of long noncoding RNA (lncRNA) nuclear paraspeckle assembly transcript 1 (NEAT1) in gastric cancer (GC) development progress.

Relative mRNA and protein expression levels were quantified by quantitative Reverse Transcription-PCR (qRT-PCR) or Western blot analysis. Cell proliferation and cell apoptosis were measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay and flow cytometry, respectively. Binding sites of miR-497-5p on NEAT1 or phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) were determined by RNA pull-down assay or dual-luciferase reporter assay. Finally, the tumorigenic role of NEAT1 in GC was assessed using a xenograft model on nude mice.

NEAT1 was upregulated in GC tissues, promoted proliferation, and inhibited apoptosis of GC cells. NEAT1 could directly bind to and negatively regulate miR-497-5p expression. PIK3R1 was then identified as a downstream target of miR-497-5P. In GC cell models, PIK3R1 was found to be directly negatively regulated by miR-497-5p and indirectly positively regulated by NEAT1. Finally, NEAT1 knockdown inhibited tumor growth, increased miR-497-5p expression, and decreased PIK3R1 expression in xenograft model mice compared with the negative control.

Functioned as an oncogene, NEAT1 promoted cell growth in GC by regulating miR-497-5p/PIK3R1 axis. These results provided valuable insights into the underlying regulation signaling in gastric cancer development, shedding light on NEAT1 a promising therapeutic target from bench to clinic.